About five million Americans suffer from genital herpes, with an estimated one-half million individuals having become infected in 1981 alone. Although many forms of therapy have been tested, none has proven profoundly beneficial in decreasing the severity and frequency of the clinical manifestations. Interferon seems to have especially high potential for the treatment of herpes, condylomata acuminata and other similarly manifested disease states. However, systemic regimens adequate to suppress skin symptomology often results in adverse systemic effects and still may not overcome the inaccessibility of the target tissue to the drug. "Drug delivery" remains the singularly most limiting factor to the effective treatment of herpes. Liposomes recently have received much attention in the search for a more effective means of delivering intrinsically active drugs to their tissue targets. In recent studies, we have shown that liposomes facilitate skin deposition of drugs and that when interferon is encapsulated in a liposome, by a technique which facilitates its association with bilayers, the polypeptide penetrates intact skin and is therapeutically active; however, interferon incorporated in traditional vehicles lack therapeutic efficacy. The goal of these studies is to continue to assess the possibility of treating virus-infected epithelial cells with liposomally entrapped interferon delivered by the transdermal route. Specifically, we wish to optimize interferon formulations to maximize both liposomal entrapment of biologically active interferon and its subsequent delivery through intact skin to tissue infected by virus. Since interferon's biological activity is long-lasting when in liposomes, liposomes also appear to offer a practical as well as an effective means of delivery of interferon to lesion sites.